Is there any ideas how to make custom values working correctly? about rx-sandbox

[kwonoj]

I don't think you can do this out of box, looks like you'd like to resolve marble to key but currently always falls to value to draw marbles. Main design comes due to key for marble observable is arbitrary value, actual value we care about is value itself (if key === value that doesn't matter though). Not sure if I'll spend time to create additional path for this logic.

[sharikovvladislav]

Main design comes due to key for marble observable is arbitrary value, actual value we care about is value itself (if key === value that doesn't matter though)

Thats perfect. But at the moment if you put null/undefined to the observable , you will get some stuff like ä as the output. Yeah, okay, and what is ä? What are other symbols? You don't know it at all from the output. Just debug.

Okay, so now the library works perfectly only with numbers and values which are 1-literal strings.

The test:

it('testcase', () => {
  const {hot, e, s, getMessages, flush} = rxSandbox.create();


  const values = { a: undefined };
  const source = hot('aaaaaaaaa|', values);
  const expected = e('---x--yf---|', values);
  
  const messages = getMessages(source.pipe(mapTo(undefined)));
  flush();

  marbleAssert(messages).to.equal(expected);
});

Output:

        Error: 
        "Source:   äḅċḋëḟġḧï|"
        "Expected: ---x--yf---|"

It is simple observable which emits undefined N times. Cool. And we got äḅċḋëḟġḧï| as output. Well, that makes sense. Developer experience.

Main design comes...

Values in the observables in test are not random. You write test, you pass test data, you know what values you will pass and what values are expected. That is how unit testing works.
Even some kind of fn as value can be passed, when you will determine symbol based on some logic (complex objects, you can use type guards).